Hradilová Iveta, Trněný Oldřich, Válková Markéta, Cechová Monika, Janská Anna, Prokešová Lenka, Aamir Khan, Krezdorn Nicolas, Rotter Björn, Winter Peter, Varshney Rajeev K, Soukup Aleš, Bednář Petr, Hanáček Pavel, Smýkal Petr
Department of Botany, Palacký University in OlomoucOlomouc, Czechia.
Department of Plant Biology, Mendel University in BrnoBrno, Czechia.
Front Plant Sci. 2017 Apr 25;8:542. doi: 10.3389/fpls.2017.00542. eCollection 2017.
The origin of the agriculture was one of the turning points in human history, and a central part of this was the evolution of new plant forms, domesticated crops. Seed dispersal and germination are two key traits which have been selected to facilitate cultivation and harvesting of crops. The objective of this study was to analyze anatomical structure of seed coat and pod, identify metabolic compounds associated with water-impermeable seed coat and differentially expressed genes involved in pea seed dormancy and pod dehiscence. Comparative anatomical, metabolomics, and transcriptomic analyses were carried out on wild dormant, dehiscent (JI64, VIR320) and cultivated, indehiscent non-dormant (JI92, Cameor) and recombinant inbred lines (RILs). Considerable differences were found in texture of testa surface, length of macrosclereids, and seed coat thickness. Histochemical and biochemical analyses indicated genotype related variation in composition and heterogeneity of seed coat cell walls within macrosclereids. Liquid chromatography-electrospray ionization/mass spectrometry and Laser desorption/ionization-mass spectrometry of separated seed coats revealed significantly higher contents of proanthocyanidins (dimer and trimer of gallocatechin), quercetin, and myricetin rhamnosides and hydroxylated fatty acids in dormant compared to non-dormant genotypes. Bulk Segregant Analysis coupled to high throughput RNA sequencing resulted in identification of 770 and 148 differentially expressed genes between dormant and non-dormant seeds or dehiscent and indehiscent pods, respectively. The expression of 14 selected dormancy-related genes was studied by qRT-PCR. Of these, expression pattern of four genes: porin (MACE-S082), peroxisomal membrane PEX14-like protein (MACE-S108), 4-coumarate CoA ligase (MACE-S131), and UDP-glucosyl transferase (MACE-S139) was in agreement in all four genotypes with Massive analysis of cDNA Ends (MACE) data. In case of pod dehiscence, the analysis of two candidate genes ( and ) and three out of 20 MACE identified genes (MACE-P004, MACE-P013, MACE-P015) showed down-expression in dorsal and ventral pod suture of indehiscent genotypes. Moreover, MACE-P015, the homolog of peptidoglycan-binding domain or proline-rich extensin-like protein mapped correctly to predicted locus on PsLGIII. This integrated analysis of the seed coat in wild and cultivated pea provides new insight as well as raises new questions associated with domestication and seed dormancy and pod dehiscence.
农业的起源是人类历史上的转折点之一，其中的核心部分是新植物形态即驯化作物的进化。种子传播和萌发是被选择来促进作物种植和收获的两个关键特性。本研究的目的是分析种皮和豆荚的解剖结构，鉴定与不透水种皮相关的代谢化合物以及参与豌豆种子休眠和豆荚开裂的差异表达基因。对野生休眠、易裂（JI64、VIR320）以及栽培的、不易裂、非休眠（JI92、Cameor）豌豆品种和重组自交系（RILs）进行了比较解剖学、代谢组学和转录组学分析。发现种皮表面质地、大石细胞长度和种皮厚度存在显著差异。组织化学和生化分析表明，大石细胞内种皮细胞壁的组成和异质性存在基因型相关变异。对分离的种皮进行液相色谱 - 电喷雾电离/质谱和激光解吸/电离 - 质谱分析发现，与非休眠基因型相比，休眠基因型中原花青素（表儿茶素二聚体和三聚体）、槲皮素、杨梅素鼠李糖苷和羟基化脂肪酸的含量显著更高。通过高分辨率RNA测序的分离群体分析法分别鉴定出休眠和非休眠种子之间以及易裂和不易裂豆荚之间770个和148个差异表达基因。通过qRT - PCR研究了14个选定的与休眠相关基因的表达。其中，四个基因：孔蛋白（MACE - S082）、过氧化物酶体膜PEX14样蛋白（MACE - S108）、4 - 香豆酸辅酶A连接酶（MACE - S131）和UDP - 葡萄糖基转移酶（MACE - S139）在所有四种基因型中的表达模式与cDNA末端大规模分析（MACE）数据一致。在豆荚开裂方面，对两个候选基因（和）以及20个MACE鉴定基因中的三个（MACE - P004、MACE - P013、MACE - P015）的分析表明，在不易裂基因型的豆荚背缝线和腹缝线中表达下调。此外，MACE - P015，即肽聚糖结合结构域或富含脯氨酸的伸展蛋白样蛋白的同源物，正确定位到PsLGIII上的预测位点。对野生和栽培豌豆种皮的这种综合分析提供了新的见解，同时也提出了与驯化、种子休眠和豆荚开裂相关的新问题。
